Aromadendrene

Leaf essential oils were obtained by hydrodistillation (100 g leaves) using a Clevenger type apparatus for 3 h. The essential oils were collected in dichloromethane, dried over silica gel, and stored at 4 °C in amber glass vials until analysis. Essential oil yield was calculated on a moisture-free basis as 0.08–0.19% (w/w). GC-MS used an Agilent technologies 7820A instrument with a HP-5 capillary columns (30 m × 0.32 mm I.D. covered with a 0.25 µm of 5:95 phenyl-dimethylpolysiloxane plate). The mobile phase was helium at 1 mL min⁻¹ flow rate and 180 °C injector temperature; the oven program was from 60 °C for 3 min, 75 °C for 5 min, 150 °C for 10 min, and up to 250 °C for 20 min. Software was set for 30–600 m/z range, and the mass spectra was recorded at 70 eV. The relative retention index (RRI) was calculated with a standard mix of C₈–C₂₀n-alkanes (Sigma-Aldrich Co., St Louis, MO, USA) under identical conditions [74 (link)]. Data were compared with the NIST 2.0 database, with authentic d-limonene, β-linalool, β-caryophyllene, caryophyllene oxide, and (+) aromadendrene standards (Sigma-Aldrich Co., St Louis, MO, USA) and related literature [75 ,76 ]. The percentage of abundance was calculated from GC chromatograms.

Aromadendrene, Borneol, α-Bisabolol, Camphene, Carvacrol, Caryophyllene oxide, 1,8-Cineole, α-Humulene, Limonene, Linalool, (E)-β-Ocimene, α-Phellandrene, α-Pinene, β-Pinene, Sabinene, α-Terpinene, γ- Terpinene, Terpinen-4-ol, α-Terpineol, α-Thujene, Thymol, soluble starch, DNSA (dinitrosalicylic acid), were purchased from Sigma Aldrich (Milan, Italy). Sodium tartrate, sodium potassium tartrate, sodium acetate were bought from Merck (Darmstadt, Germany).

The chemical standards used, namely ocimene (94%); limonene (96%) and α-humulene (96%); myristicin and aromadendrene (97%); α-pinene and β-pinene (98%); linalool, 1,8-cineole, β-caryophyllene, eugenol, pentadecane, heptadecane and tetradecanol (99.0%) were all purchased from Sigma-Aldrich (Saint Louis, MO, USA).
Dillapiole, asaricin, and safrole, all with a purity higher than 99.7%, were obtained via fractional distillation, as described in Section 4.2.